Conflict detection and resolution is a complex topic. There are a host of references on conflict detection. FIG. 1 shows a representative and comprehensive Policy Based Network Management (PBNM) system known in the art. This architecture explicitly identifies five different levels of conflict detection and resolution: globally between policy servers, globally across the different components of a particular policy server, locally for all Policy Decision Points (PDPs) in a domain of a policy server, local to a particular PDP within a specific domain of a given policy server, and local per device (i.e., a PEP) in a domain.
The architecture shown in FIG. 1 is based on the following definition of a policy conflict:
A policy conflict occurs when the conditions of two or more policy rules that apply to the same set of managed objects are simultaneously satisfied, but the actions of two or more of these policy rules conflict with each other.
A simplified model of a policy rule is a triplet, consisting of three clauses: event, condition, and action. Events are used to trigger the evaluation of a policy rule; conditions specify if the policy rule is applicable, and actions define what to do. Therefore, there are three main types of conflicts that can occur in a PBNM system. The conflicts include conflicts between different policy rules; conflicts between the actions within a policy rule; and conflicts between policy rules within a policy rule (e.g., sub-rules within a rule).
Unfortunately, this architecture does not address semantic conflicts. Semantics are neither considered in the definition of a policy conflict, nor in the definition of a policy rule. This is true of all other policy rule definitions in the existing art.
There are mechanisms known in the art to detect policy conflicts. However, these mechanisms fail to detect all of the above-mentioned types of policy conflicts. For example, two policies could pass all tests for conflicts and still have semantic conflicts (e.g., two policies that, when instantiated, have conflicting side effects, or conflicting directives based on different meanings).
Therefore, a need exists to overcome the problems with the prior art as discussed above.